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    <title>Apache Server Frequently Asked Questions</title>
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    <h1 align="CENTER">Apache Server Frequently Asked
    Questions</h1>

    <p>$Revision: 1.3 $ ($Date: 2001/10/08 01:26:54 $)</p>

    <p>The latest version of this FAQ is always available from the
    main Apache web site, at &lt;<a
    href="http://httpd.apache.org/docs/misc/FAQ.html"
    rel="Help"><samp>http://httpd.apache.org/docs/misc/FAQ.html</samp></a>&gt;.</p>
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    <p>If you are reading a text-only version of this FAQ, you may
    find numbers enclosed in brackets (such as "[12]"). These refer
    to the list of reference URLs to be found at the end of the
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    for the hypertext version.</p>

    <h2>The Questions</h2>

    <ol type="A">
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      <li value="3">
        <strong>Building Apache</strong> 

        <ol>
          <li><a href="#bind8.1">Why do I get an error about an
          undefined reference to "<samp>__inet_ntoa</samp>" or
          other <samp>__inet_*</samp> symbols?</a></li>

          <li><a href="#cantbuild">Why won't Apache compile with my
          system's <samp>cc</samp>?</a></li>

          <li><a href="#linuxiovec">Why do I get complaints about
          redefinition of "<code>struct iovec</code>" when
          compiling under Linux?</a></li>

          <li><a href="#broken-gcc">I'm using gcc and I get some
          compilation errors, what is wrong?</a></li>

          <li><a href="#glibc-crypt">I'm using RedHat Linux 5.0, or
          some other <samp>glibc</samp>-based Linux system, and I
          get errors with the <code>crypt</code> function when I
          attempt to build Apache 1.2.</a></li>
        </ol>
      </li>
      <!--#endif -->
      <!--#if expr="$STANDALONE" -->
    </ol>
    <hr />

    <h2>The Answers</h2>
    <!--#endif -->
    <!--#if expr="! $TOC" -->

    <h3>C. Building Apache</h3>

    <ol>
      <li>
        <a id="bind8.1" name="bind8.1"><strong>Why do I get an
        error about an undefined reference to
        "<samp>__inet_ntoa</samp>" or other <samp>__inet_*</samp>
        symbols?</strong></a> 

        <p>If you have installed <a
        href="http://www.isc.org/bind.html">BIND-8</a> then this is
        normally due to a conflict between your include files and
        your libraries. BIND-8 installs its include files and
        libraries <code>/usr/local/include/</code> and
        <code>/usr/local/lib/</code>, while the resolver that comes
        with your system is probably installed in
        <code>/usr/include/</code> and <code>/usr/lib/</code>. If
        your system uses the header files in
        <code>/usr/local/include/</code> before those in
        <code>/usr/include/</code> but you do not use the new
        resolver library, then the two versions will conflict.</p>

        <p>To resolve this, you can either make sure you use the
        include files and libraries that came with your system or
        make sure to use the new include files and libraries.
        Adding <code>-lbind</code> to the
        <code>EXTRA_LDFLAGS</code> line in your
        <samp>Configuration</samp> file, then re-running
        <samp>Configure</samp>, should resolve the problem. (Apache
        versions 1.2.* and earlier use <code>EXTRA_LFLAGS</code>
        instead.)</p>

        <p><strong>Note:</strong>As of BIND 8.1.1, the bind
        libraries and files are installed under
        <samp>/usr/local/bind</samp> by default, so you should not
        run into this problem. Should you want to use the bind
        resolvers you'll have to add the following to the
        respective lines:</p>

        <dl>
          <dd><code>EXTRA_CFLAGS=-I/usr/local/bind/include<br />
           EXTRA_LDFLAGS=-L/usr/local/bind/lib<br />
           EXTRA_LIBS=-lbind</code></dd>
        </dl>
        <hr />
      </li>

      <li>
        <a id="cantbuild" name="cantbuild"><strong>Why won't Apache
        compile with my system's <samp>cc</samp>?</strong></a> 

        <p>If the server won't compile on your system, it is
        probably due to one of the following causes:</p>

        <ul>
          <li><strong>The <samp>Configure</samp> script doesn't
          recognize your system environment.</strong><br />
           This might be either because it's completely unknown or
          because the specific environment (include files, OS
          version, <em>et cetera</em>) isn't explicitly handled. If
          this happens, you may need to port the server to your OS
          yourself.</li>

          <li><strong>Your system's C compiler is
          garbage.</strong><br />
           Some operating systems include a default C compiler that
          is either not ANSI C-compliant or suffers from other
          deficiencies. The usual recommendation in cases like this
          is to acquire, install, and use <samp>gcc</samp>.</li>

          <li><strong>Your <samp>include</samp> files may be
          confused.</strong><br />
           In some cases, we have found that a compiler
          installation or system upgrade has left the C header
          files in an inconsistent state. Make sure that your
          include directory tree is in sync with the compiler and
          the operating system.</li>

          <li><strong>Your operating system or compiler may be out
          of revision.</strong><br />
           Software vendors (including those that develop operating
          systems) issue new releases for a reason; sometimes to
          add functionality, but more often to fix bugs that have
          been discovered. Try upgrading your compiler and/or your
          operating system.</li>
        </ul>

        <p>The Apache Group tests the ability to build the server
        on many different platforms. Unfortunately, we can't test
        all of the OS platforms there are. If you have verified
        that none of the above issues is the cause of your problem,
        and it hasn't been reported before, please submit a <a
        href="http://httpd.apache.org/bug_report.html">problem
        report</a>. Be sure to include <em>complete</em> details,
        such as the compiler &amp; OS versions and exact error
        messages.</p>
        <hr />
      </li>

      <li>
        <a id="linuxiovec" name="linuxiovec"><strong>Why do I get
        complaints about redefinition of "<code>struct
        iovec</code>" when compiling under Linux?</strong></a> 

        <p>This is a conflict between your C library includes and
        your kernel includes. You need to make sure that the
        versions of both are matched properly. There are two
        workarounds, either one will solve the problem:</p>

        <ul>
          <li>Remove the definition of <code>struct iovec</code>
          from your C library includes. It is located in
          <code>/usr/include/sys/uio.h</code>.
          <strong>Or,</strong></li>

          <li>Add <code>-DNO_WRITEV</code> to the
          <code>EXTRA_CFLAGS</code> line in your
          <samp>Configuration</samp> and reconfigure/rebuild. This
          hurts performance and should only be used as a last
          resort.</li>
        </ul>
        <hr />
      </li>

      <li>
        <a id="broken-gcc" name="broken-gcc"><strong>I'm using gcc
        and I get some compilation errors, what is
        wrong?</strong></a> 

        <p>GCC parses your system header files and produces a
        modified subset which it uses for compiling. This behavior
        ties GCC tightly to the version of your operating system.
        So, for example, if you were running IRIX 5.3 when you
        built GCC and then upgrade to IRIX 6.2 later, you will have
        to rebuild GCC. Similarly for Solaris 2.4, 2.5, or 2.5.1
        when you upgrade to 2.6. Sometimes you can type "gcc -v"
        and it will tell you the version of the operating system it
        was built against.</p>

        <p>If you fail to do this, then it is very likely that
        Apache will fail to build. One of the most common errors is
        with <code>readv</code>, <code>writev</code>, or
        <code>uio.h</code>. This is <strong>not</strong> a bug with
        Apache. You will need to re-install GCC.</p>
        <hr />
      </li>

      <li>
        <a id="glibc-crypt" name="glibc-crypt"><strong>I'm using
        RedHat Linux 5.0, or some other <samp>glibc</samp>-based
        Linux system, and I get errors with the <code>crypt</code>
        function when I attempt to build Apache 1.2.</strong></a> 

        <p><samp>glibc</samp> puts the <code>crypt</code> function
        into a separate library. Edit your
        <code>src/Configuration</code> file and set this:</p>

        <dl>
          <dd><code>EXTRA_LIBS=-lcrypt</code></dd>
        </dl>

        <p>Then re-run <samp>src/Configure</samp> and re-execute
        the make.</p>
        <hr />
      </li>
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